Boron neutron capture therapy (BNCT) is a procedure in which tissue to be destroyed is selectively loaded with a compound containing boron-10 and subsequently exposed to thermal neutrons. The combination of the thermal neutron flux and boron concentration results in a radiation dose from the emitted alpha and Li7 particles. The dose distribution will follow the boron concentration even on a cellular level. Clinical trials of this technique were conducted at MIT-MGH in 1960-61 to treat patients with glioblastoma with uniformly negative results. During the past 15 years, studies in boron chemistry, radiation biology in animals, physics, engineering and dosimetry have been continuously conducted with major improvements in all these areas. A clinical trial of this therapy modality is currently being conducted in Japan by our colleague, Dr. Hiroshi Hatanaka with the result that glioblastoma patients treated only with BNCT are alive and well over three years after treatment. This application is to request support for an intensive program at the Massachusetts Institute of Technology in conjunction with the Massachusetts General Hospital to provide a definitive clinical trial of this promising therapy technique.